The present invention relates to bicycles and bicycle accessories, and more particularly to bicycles adapted for connection to a trailer, such as a child or bike cargo trailer or trailer cycle. It has become increasingly popular to use bicycles to pull small trailers, either for transporting children, pets and/or cargo. These trailers often are positioned low to the ground and include some type of drawbar or tongue connected to the lead bicycle. A new type of trailer is the so-called xe2x80x9ctrailer cycle,xe2x80x9d a small, single-wheeled cycle, having a seat and handlebars, connected via a tongue to the lead bicycle. A trailer cycle typically is provided with a pedal/sprocket/chain assembly. An adult can now ride the lead bicycle and pull a child behind seated on the trailer cycle. The child can pedal away, steering and learning how to ride, while being safely pulled along.
An example of a trailer cycle is disclosed in U.S. Pat. No. 5,785,335 which discloses a vehicle having a frame, a main tube extending toward the lead cycle and a hitch mechanism located between the lead cycle and the trailer cycle. The hitch mechanism is positioned substantially vertically above the hub of the lead-cycle rear wheel, and is housed in an orthogonal member which has an adjustable vertical pivot mechanism and a similarly adjustable yaw pivot mechanism. The orthogonal member is mounted on a frame construction which is rigidly connected to the bicycle on a rack frame which includes diagonal braces and supports as well as seat-stay attachments for interconnecting the rack frame to the bicycle frame. Another type of trailer cycle includes a long tongue which is connected to the seat post of the leading or pulling bicycle.
The present invention is directed to a novel hitch assembly which is mounted to a bicycle adapted for connection to the tongue of a vehicle to be trailed behind, such as a trailer cycle, which enables the trailer cycle to closely follow the steering, leaning and handling of the lead bicycle by its rider. The hitch assembly of the present invention includes a hitch unit which is mounted directly above the rear wheel and hub/axle assembly of the lead bicycle, and to which the tongue is connected. The hitch unit is rotatable about a substantially vertical first pivot axis, and includes structure for enabling the tongue to be pivoted about a substantially horizontal second pivot axis. The hitch unit is mounted on a support structure above the rear hub/axle assembly of the lead bicycle, and is connected by an adjustable stabilizer or strut member to the seat post of the bicycle.
The hitch assembly of the present invention finds particular utility when mounted on xe2x80x9csuspensionxe2x80x9d bicycles, which include a shock absorber or other structure enabling the rear wheel to move up and down relative to the seat, and substantially vertically, relative to the ground, as the bicycle encounters bumps and depressions in the road. Suspension vehicles take variant forms, but differ from conventional non-suspension bicycles by enabling relative movement of the rear wheel to the frame. Examples of suspension bicycles are those which include so-called four-bar-linkage systems, which enable the rear axle of the rear wheel, and correspondingly the rear wheel, to move relative to the seat of the bicycle, in a substantially vertical direction, providing a cushioned ride.
While the present invention has particular utility with respect to use on a suspension bicycle, because those bicycles permit up and down movement of the rear wheel relative to the frame, it can also be used on conventional bicycles without a rear-wheel suspension system. The hitch assembly enables the attached tongue of the trailer to swing about a first pivot axis, which is substantially vertical, and about a second pivot axis, which is substantially horizontal. This pivoting action enables the rider of an attached trailer cycle to feel the action of the lead bicycle, operated by an adult, as the lead bicycle negotiates turns, goes up and down hills and slopes, encounters and rides over bumps, swerves to avoid road obstacles, etc.
The hitch assembly of the present invention enables movement of the hitch unit, relative to the frame of the bicycle, by incorporation of a support structure, including vertically-mounted wheelstays, pivotally connected at their lower ends to opposite ends of a uniquely-configured skewer so that there is a pivotal connection at the hub assembly. A stabilizing member in the form of a lengthwise-adjustable strut member has a first end detachably and pivotally connected, by a releasable clamp, to the seat post of the bicycle, and a second end pivotally connected to an upper end of the wheelstay assembly adjacent the hitch unit. When this construction is used on a suspension bicycle, impact from bumps will displace the rear wheel upwardly, relative to the seat of the bicycle, and that will cause the wheelstay assembly to move upwardly also, but swing just slightly from the vertical because the hitch unit is pivotally connected to the strut member. As bumps and depressions are encountered, the wheelstays move up and down with the rear wheel.